1. Field of the Invention
The present invention relates, in a spinning machine for producing spun yarns utilizing a turning air flow, to a yarn piecing method for piecing cut or broken spun yarns.
2. Prior Art
In the conventional spinning machines for producing spun yarns utilizing a turning air flow, a yarn piecing method has been known in which when a spun yarn is cut or broken, yarn-piecing is carried out by drawing out a spinning yarn on the spinning side and a bobbin yarn on the take-up side, and introducing the spinning yarn and the bobbin yarn into a knotter.
In the spinning machines for producing spun yarns utilizing a turning air flow, a practical yarn piecing method has been known in which in the case where a spun yarn is cut due to a defect of the spun yarn itself or a defect of the apparatus, or in the case where a slub catcher disposed in the spinning machine detects a slub during spinning to forcibly cut the spun yarn, a spinning yarn on the spinning side and a bobbin yarn on the winding side are drawn out to introduce the spinning yarn and the bobbin yarn into a knotter for piecing them together. On the other hand, in the case of a spinning machine utilizing a turning air flow, for example, a spinning machine disclosed in Japanese Patent Application Laid-Open No. 161525/1991, a spun yarn is not produced merely by supplying a sliver drafted from a draft part to a spindle portion when spinning starts, and it is necessary to insert a yarn called a leading yarn (a yarn drawn from the yarn package) into the spindle portion from an outlet of the spindle. That is, it is sometimes impossible to piece a yarn to be spun from the spinning portion with a yarn on the side of a winding package.